HPC & AI: the challenges and issues related to exascale for numerical modelling and simulation

High-performance digital technology has entered a new era in recent years with the arrival of exascale. Anticipated by experts for more than ten years, exascale is supposed to respond to increasingly varied uses that go far beyond traditional numerical simulation. Data processing and AI are shaking up the HPC landscape and have implications at all levels, from hardware to software, at the scale of applications and at the scale of supercomputers, which are losing their central role in the data-processing chain. In this talk, we will present the current and future supercomputing landscape and we will illustrate with a few examples from different scientific domains (climate, health, energy,...) the issues related to exascale.